Deep brain stimulation (“DBS”) is a neuromodulation therapy effective at treating a range of neurological symptoms and conditions, including motor symptoms of patients with medication-refractory Parkinson's disease (“PD”). Tuning stimulation parameters is currently done using a time intensive trial-and-error process. For example, with DBS for treatment of motor symptoms of PD patients, high frequency stimulation (greater than 100 Hz) is conventionally tuned for each patient using a trial-and-error process. Some implantable DBS devices can simultaneously deliver stimulation while recording the neural response. As yet, these devices do not effectively use a closed-loop approach to setting stimulation parameters.
Dynamic changes in the basal ganglia network are thought to lead to motor symptoms of PD. A loss of dopaminergic inputs results in changes in firing rates and patterns of neurons within the basal ganglia. The emergence of synchronous activity, particularly in the beta range (12-35 Hz), is associated with motor symptoms in PD. Therapeutic DBS is effective at disrupting the pathological oscillation, making the beta oscillation a possible biomarker for closed-loop stimulation. Phasic stimulation may provide a closed-loop approach to disrupting this pathological beta oscillation, as stimulation at specific phases of an oscillation can either disrupt or enhance the oscillation. The frequency of stimulation affects therapeutic outcome in DBS for PD (e.g., frequencies greater than 100 Hz are therapeutic). This may be because stimulation at certain frequencies results in more stimulus pulses occurring at the optimal phase for desynchronization than at other frequencies.
There remains a need, however, to provide systems and methods that are capable of determining optimized settings for delivering electrical stimulations using a closed-loop stimulation system.